<!doctype html>
<canvas></canvas>
<script>
var canvas = document.body.firstChild,
    gl = canvas.getContext("experimental-webgl");
gl.texImage2D(0, 0, 0, 0, 0, { get width() { throw 7 }, get height() { throw 7 }, data: new Uint8ClampedArray(10) });
gl.texSubImage2D(0, 0, 0, 0, 0, 0, { get width() { throw 7 }, get height() { throw 7 }, data: new Uint8ClampedArray(10) });
</script>